The Church of Saint Charles at the Four Fountains is a Roman Catholic church in Rome, Italy. Designed by the architect Francesco Borromini, it was his first independent commission. It is an iconic masterpiece of Baroque architecture, built as part of a complex of monastic buildings on the Quirinal Hill for the Spanish Trinitarians, an order dedicated to the freeing of Christian slaves. He received the commission in 1634, under the patronage of Cardinal Francesco Barberini, whose palace was across the road. However, this financial backing did not last and subsequently the building project suffered various financial difficulties. It is one of at least three churches in Rome dedicated to San Carlo, including San Carlo ai Catinari and San Carlo al Corso.

My own exploration:

Keywords: Interior

Interior

The church interior is both extraordinary and complex. There are three principal parts that was identified vertically as the lower order at ground level, the transition zone of the pendentives and the oval coffered dome with its oval lantern.

In the lower part of the church, the main altar is on the same longitudinal axis as the door and there are two altars on the cross axis. Between these, and arranged in groups of four, sixteen columns carry a broad and continuous entablature. The arrangement seems to refer to a cross plan but all the altars are visible as the two central columns in each arrangement of four are placed on the oblique with respect to the axial ordering of the space. This creates an undulating movement effect which is enhanced by the variation in treatment of the bays between the columns with niches, mouldings, and doors. Architectural historians have described how the bay structure of this lower order can have different rhythmic readings and the underlying geometric rationale for this complex ground plan, as well as discussing the symbolism of the church and the distinctive architectural drawings of Borromini.

The dome with its intricate geometrical pattern

The pendentives are part of the transition area where the undulating almost cross-like form of the lower order is reconciled with the oval opening to the dome. The arches which spring from the diagonally placed columns of the lower wall order to frame the altars and entrance, rise to meet the oval entablature and so define the space of the pendentives in which roundels are set.

The oval entablature to the dome has a ‘crown’ of foliage and frames a view of deep set interlocking coffering of octagons, crosses and hexagons which diminish in size the higher they rise. Light floods in from windows in the lower dome that are hidden by the oval opening and from windows in the side of the lantern. In a hierarchical structuring of light, the illuminated lantern with its symbol of the Holy Trinity is the most brightly lit, the coffering of the dome is thrown into sharp and deep relief and light gradually filters downwards to the darker lower body of the church.